Polymer thin film transistors have potential applications for fabricating low-cost integrated circuits for large-area/low-end electronic devices such as active matrix liquid crystal displays, electronic paper, smart cards, radio frequency identification tags, and the like. They have the added advantages of being mechanically durable and compatible with flexible substrates, thus offering the potential of fabricating structurally flexible electronic devices. Two critical requirements for these low-cost applications are sufficient charge carrier mobility and solution processability.
Higher charge carrier mobility can be achieved through enabling material design and process innovation as disclosed in PCT WO 00/79617 A1 and Yiliang Wu et al., U.S. Ser. No. 10/273,901 (filed on Oct. 17, 2002) titled “Process and Device Using Self-Organizable Polymer.” Solution processability of materials at room temperature or other temperatures slightly above room temperature is generally advantageous due to the lower energy requirement and the simplification in equipment. However, certain polymers may gel at these temperatures which renders the gelled composition unable to be satisfactorily solution coated. Thus, there is a need, which the present invention addresses, for new techniques to enable the fabrication of polymer thin film transistors at a temperature lower than an elevated temperature using polymers that are capable of gelling.
The following documents also may be relevant:
F. Brustolin et al., “Highly Ordered Structures of Amphiphilic Polythiophenes in Aqueous Media,” Macromolecules, Vol. 35, pp. 1054-1059 (published on web Jan. 3, 2002).
G. Dufresne et al., “Thermochromic and Solvatochromic Conjugated Polymers by Design,” Macromolecules, Vol. 33, pp. 8252-8257 (published on web Sep. 30, 2000).
M. Leclerc, “Optical and Electrochemical Transducers Based on Functionalized Conjugated Polymers, Adv. Mater., Vol. 11, No. 18, pp. 1491-1498 (1999).